Relationship between maximal stroke volume and lower boundary of severe exercise domain

BACKGROUND: Minimal workload to elicit peak O-2 consumption (P-min(V) O-2peak) is accepted as sufficient exercise intensity to improve maximal O-2 consumption ((V) over dot O-2max), and stroke volume (SV) is the most important component of the (V) over dot O-2max. the aim of the study was to examine whether cyclists' maximal SV responses (SVmax) closely related to P-min(V) O-2peak, or not. METHODS: Ventilatory threshold (VT) was measured by incremental tests. Then, constant-load verifications were performed to reveal the (V) over dot O-2max. the SVmax was analysed by constant-load exercises performed in the range of 40% and 100% of (V) over dot O-2max. Cyclists' critical power (CP) was estimated based on the data obtained from four constant-load exhaustive tests. the P-min(V) O-2peak was accepted as the first work rate to elicit 5% closer (V) over dot O-2 responses to (V) over dot O-2max were attained. After repeated-measures analyses, possible significant differences investigated by LSD, and correlations were analysed by Pearson r. RESULTS: the CP means were significantly lower than the P-min(V) O-2peak (295.4 +/- 40.2 W vs. 306.7 +/- 49 W; P<0.05). Fractional usages of (V) over dot O-2max belonging to the CP and P-min(V) O-2peak corresponded to 92% and 96% of (V) over dot O-2max, respectively. Moreover, P-min(V) O-2peak was greater than the power output at SVmax (P-SVmax) (214.1 +/- 60 W; P<0.05). There were weak correlations between P-SVmax and P-min(V) O-2peak (r: 0.30), P-SVmax and CP (r: 0.24); however, there were moderate correlations between SVmax and P-min(V) O-2peak (r: 0.64), SVmax and the CP (r: 0.66). CONCLUSIONS: in conclusion, a greater value of SVmax may cause a significant performance gain by decreasing the gap between P-(V) over dot O-2max and P-min(V) O-2peak.